<header>
  <div class="container">
    <img src="../img/logo.png" alt="Noodle logo" class="logo">
    <nav>
      <ul>
        <li><a href="teacher.php"></a></li>
        <?php
          if(isset($_POST['chapterPanel']) || isset($_SESSION['chapterPanel']))
          {           
            echo  '<li><a href="startQuestions.php">Create questions</a></li>'; 
          }
        ?>             
        <li><a href="goBack.php">Back</a></li>
        <li><a href="../logout.php">Logout</a></li>
      </ul>
    </nav>
  </div>
</header>